1. Field of the Invention
The present invention relates to an information communicating apparatus, a method and a system therefor, and more particularly to technology of communication of digital information with a digital interface.
2. Related Background Art
There has recently been developed a communication system in which a personal computer (PC) is connected with a digital video camera (DVC) through a digital interface and the image taken with the digital video camera is supplied to the personal computer in the form of digital signal and is freely edited on the personal computer.
Among the digital interface technologies usable for constituting such communication system, there is known the IEEE Standard for a High Performance Serial Bus (hereinafter called IEEE 1394-1995 standard).
In the communication system constructed with the digital interface of the IEEE 1394-1995 standard, the communication between the devices is controlled by a node ID, which is the ID information for communication control. The node ID is automatically assigned to each device at each activation of the bus resetting.
The bus resetting is activated at the start of power supply, an addition or a deletion of a device to or from the network, or the reception of a bus reset command from any device. After the bus resetting is activated, the system automatically recognizes the new connection configuration of the network and automatically resets the node ID assigned to each device.
Also, each device constituting the communication system is, in advance, given specific ID information which is not changed by the activation of the bus resetting (hereinafter called the unique ID).
In such a communication system, the node ID may be different before and after the bus resetting, and there has been required a system capable of appropriately handling such change.
Also, in such communication system, it has not been possible to obtain, from the unique ID or the node ID mentioned above, the information indicating the functions or features of each device.
For example, in case of editing or processing, in the personal computer (PC) on the communication system, the image information obtained from the plural digital video cameras (DVC) connected to the same communication system, there are required information on the image taken by each DVC (for example information on the image format or the data compression encoding method) and information on the camera unit provided in each DVC (for example information on the filter).
For obtaining such information, the PC has to follow a predetermined communication procedure utilizing, for example, a command transaction set (CTS). Consequently, the number of communications becomes larger and a very cumbersome procedure is required with the increase of the number of required information or of the number of devices to be inquired.